Device for simultaneously controlling a plurality of variable resistors

ABSTRACT

A bearing having a spherical bearing surface and made of a synthetic resin by molding or the like is attached to an opening formed at the center of the top wall of a casing having four side walls. The bearing rotatably receives a spherical body having a control shaft which extends through the center of the spherical body and is securely fixed thereto. Variable resistors are attached to the side walls of the casing in such a manner that their rotary shafts may extend into the casing. Each of the opposed pairs of the variable resistors are interconnected with a bow-shaped elastic connecting member having an axially elongated slot. The lower end of the control shaft is fitted into the axially elongated slots of the connecting members which cross each other, but do not interfere with each other. As the control shaft is rotated or inclined in any direction, two or four variable resistors may be simultaneously controlled.

Wilson 338/128 D United States Patent 1 11 1 3,760,320 Oka et al. Sept.18, 1973 DEVICE FOR SIMULTANEOUSLY 3,308,675 3/1967 Jonsson 74/471 XYCONTROLLING A PLURALITY 01 2,201,686 5/1940 Marsten.... 338/174 X2,984,720 5/1961 Fischer 74/471 XY UX VARIABLE RESISTQRS 2,762,2349/1956 Dodd 74/471 XY [75] Inventors: Shunzo Olta, Osaka; Matsuo3,365,975 1/1968 Hathaway 338/128 X Nishioka, Nishinomiya-shi, both ofJapan Primary Examiner-Bernard A. Gilheany Assistant Examiner-D. A. Tone[73] Assignee: Matsushita Electric Industrial Co., 4

Ltd, Kadomwshi osakaffu Japan Attorney Milton J. Wayne et al. [22]Filed: Mar. 21, 1972 I [57] ABSTRACT [211 App]. No; 236,681 A bearinghaving a spherical bearing surface and made of a synthetic resin bymolding or the like is attached to an opening formed at the center ofthe top wall of fl Application Data a casing having four side walls. Thebearing rotatably Mar. 25, 1971 Japan 46/21457 receives a spherical bodyhaving a control shaft which Mar. 25, 1971 Japan 46/21458 extendsthrough the center of the spherical body and is Mar. 26, I971 Japan46/22058 securely fixed thereto. Variable resistors are attached Mar.26, 1971 Japan... 46/22059 to the side walls of the casing in such amanner that I their rotary shafts may extend into the casing. Each of[52] US. Cl. 338/128, 74/471 XY, 287/52.02, the opposed pairs of thevariable resistors are intercon- 1 I 287/53 H nected with a bow-shapedelastic connecting member [5 1] Int. Cl. H0lc 9/00 having an axiallyelongated slot. The lower end of the [58] Field of Search 338/128;74/471 XY; control shaft is fitted into the axially elongated slots of287/52.02,' 53 R, 53 H the connecting members which cross each other,but v do not interfere with each other. As the control shaft [56]References Cited is rotated or inclined in any direction, two or fourvari- TE STATES T able resistors may be simultaneously controlled.

y X 6 Claims, 12 Drawing Figures PATENTEDSEP 1 81m sum 3 0f 4 FIG.

FIG. 9

DEVICE FOR SIMULTANEOUSLY CONTROLLING A PLURALITY OF VARIABLE RESISTORSBACKGROUND OF THE INVENTION The present invention relates to generally adevice for controlling variable resistors and more particularly a devicefor simultaneously controlling a plurality of variable resistors.

In the prior art devices for simultaneously controlling a plurality ofvariable resistors, the rotary shafts of a pair of variable resistorswhich are attached to a pair of opposed walls of a first casing arefixed to a pair of opposed walls of a second casing respectively, andanother pair of variable resistors are attached to the other pair ofopposed side walls of the second casing. A control shaft is fixed to therotary shafts of the other pair of variable resistors. The prior artdevices of the type described therefore comprise a large number ofcomponents, and it is difficult to make them compact in size and areexpensive to manufacture.

SUMMARY OF THE INVENTION Briefly stated, a device for controllingsimultaneously a plurality of variable resistors in accordance with thepresent invention comprises a box-shaped casing having a top wall andside walls, a plastic-molded bearing having a spherical bearing surface,and attached to an opening formed in the top wall of the casing, aspherical body which is rotatably received by the bearing and has acontrol shaft which extends throughthe center of the sphericalbody andis securely attached thereto, variable resistors attached to the sidewalls of the casing respectively in such a manner that the shafts of thevariable resistors may extend into the casing through the side wallsthereof, and bow-shaped elastic connecting members each of which isprovided with an axially elongated slot and interconnects the rotaryshafts of a pair of opposed variable resistors, the lower end of thecontrol shaft being fitted into the axially elongated slots of theconnecting members. When the control shaft is rotated or inclined to adesired direction, two or four variable resistors may be simultaneouslycontrolled. Because of the connecting members of the present invention,the device can be made extremely simple in construction.

According to one embodiment of the present invention, the secureconnection between the rotary shafts of the variable resistors and theconnecting members can be made in a very simple manner because a cutoutportion at the end of each rotary shaft is fitted into an opening ateach end of the connecting members which is formed when an ear is struckout, and is securely held in position by this ear.

According to another embodiment of the present invention, a stop memberis formed integral with the bearing to extend downwardly in order tolimit the angular movement of the control shaft. Therefore, the maximumangle of inclination of the control shaft relative to the verticaldirection may be uniformly limited in all directions, and the controloperation may be greatly facilitated.

According to another embodiment of the present invention, the endportion of the control shaft is fitted with aninsulating tube having asmooth surface in order to provide electrical insulation between thecontrol shaft and the connecting members and to ensure smooth slidingcontact therebetween. Alternatively,

the connecting members may be provided with insulating coatings.

According to another embodiment of the present invention, the controlshaft is electrically connected to the connecting members so that thenoise which tends to be produced in operation may be prevented.

The above and other features and advantages of the present inventionwill become more apparent from the following description of thepreferred embodiments thereof taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a firstembodiment of a device for simultaneously controlling a plurality ofvariable resistors in accordance with the present invention;

- FIG. 2 is a bottom view thereof;

FIG. 3 is a fragmentary sectional view thereof, on an enlarged scale;

FIGS. 4 and 5 are perspective views used for explanation of theconnection between a connecting member and a rotary shaft of a variableresistor;

FIGS. 6 and 7 are perspective views used for explanation of theconnection between the lower end of the control shaft and the connectingmembers;

FIGS. 8 and 9 are perspective views illustrating a variation of theconnection between the control shaft and the connecting members;

7 FIG. 10 is a side view of a variation of the present invention inwhich the control shaft is electrically connected to the connectingmembers;

FIG. 11 is a bottom view thereof; and

FIG. 12 is a fragmentary sectional view thereof on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-5, thefirst embodiment of the present invention will be described. Abox-shaped casing 1, has an open bottom and an opening 2 therethrough towhich are attached with rivets S respective upper and lower bearings 3and 4 which are made of a synthetic resin by molding and which havespherical bearing surfaces. As best shown in FIG. 3, a spherical body 8having a control shaft 7 extending axially thereof is rotatably receivedby these bearings 3 and 4. A seat member 9 is formed integral with thelower bearing 4 to extend downwardly in order to limit the angularmovement of the control shaft 7. Variable resistors l0, 11, 12 and 13 ofthe conventional type are attached to the side walls of the casing 1 asbest shown in FIG. 2. Ears 18-21 struck out of shielding disks 14-17 ofthe variable resistors 10-13 are fitted into slots (not shown) of theside walls of the casing and are folded back in order to securely attachthe variable resistors 10-13 to the casing l. Shafts 22, 23, 24 and 25of the variable resistors 10-13 which are normally made of an insulatingmaterial are extended into the casing 1 through holes (not shown) of theside walls, and, as best shown in FIGS. 4 and 5, the end portions of theshafts 22-25 are cut out as indicated by cutout 36 for shaft 22 andcutout 38 for shaft 24 (see FIG. 2). The pairs of shafts 22-25 which arein opposed relation are interconnected with connecting members 26 and 27as best shown in FIG. 2 which are made of an elastic material and aresimilar in construction so that it will suffice to explain only one ofthem. As best shown in FIG. 5 both ends of the connecting member 27 haveears (31 is not shown) struck out therefrom with one ear 28 struck outto form a receiving hole 28a, and, as best shown in FIG. 4, the cutoutportion 36 of the shaft 22 is fitted into the receiving hole 28a, andthe ear 28 is pressed against the cutout portion 36 in order to securelyfix the shaft 22 of the variable resistor to the connecting member 27.Thus as best shown in FIGS. 1 and 2, the first pair of opposing shafts22 and 24 and the second pair of opposing shafts 23 and 25 areinterconnected with the bow-shaped connecting members 27 and 26,respectively, which cross each other but do not interfere with themovement of the other member as shown in FIG. 2. These connectingmembers 26 and 27 have axially elongated slots 32 and 33 respectively asbest shown in FIG. 2, and a lower portion 34 of the control shaft 7 isfitted into these elongated slots 32 and 33 as show most clearly in FIG.6. The lower end portion 34 of the control shaft 7 is fitted with aninsulating tubular member 35 (see FIG. 6) in order to provide theelectrical insulation between the two connecting members 26 and 27.

Next the mode of operation will be described. Since the spherical body 8is rotatably received by the bearings 3 and 4, the free angular movementof the control shaft 7 is permitted. Since they lower portion 34 of thecontrol shaft 7 is fitted into the axial elongated slots 32 and 33 ofthe connecting members 26 and 27, as the control shaft 7 is rotated, thelower portion 34 thereof slides in the axially elongated slots so thatthe connecting members 26 and 27 may rotate about the axes of the shafts22-25 ofv the variable resistors 10-13, thereby causing the shafts 22-25to rotate. Therefore, it is readily seen that when the control shaft 7is rotated, all variable resistors 10-13 may simultaneously change theirmagnitudes of resistance. For example, when it is desired to change themagnitudes of resistance of the two variable resistors 10 and 12 or 11and 13, one may rotate the control shaft 7 in the plane perpendicular tothe common axis of the shafts 22 and 24 of the resistors 10 and 12 or 23and 25 of the resistors 11 and 13 so that the lower portion 34 of thecontrol shaft 7 may slide only in the axially elongated slot 32 or 33 ofthe connecting member 26 and 27 and may cause the connecting member 27or 26 to rotate thereby rotating the shafts 22 and 24 or 23 and 25simultaneously.

According tothe present invention, the control shaft 7 is interconnectedto the shafts 22-25 of the variable resistors 10-13 through thebow-shaped elastic connecting members 26, 27 so that the connectionbetween the control shaft 7 and the shafts 22-25 of the variableresistors 10-13 may be greatly simplified.

The connection between the connecting members 26, 27 and the shafts22-25 of the variable resistors 10-13 with screws is undesirable becausea number of components is increased and, the assembly becomes complex,and an additional machining step for providing tapped holes in theshafts of the variable resistors is required. However, according to thepresent invention, the cutout portions of the shafts of the variableresistors are fitted into the holes of the connecting members 26, 27,such as cutout 36 fitted into hole 28a. Further the ears or struck-outportions are pressed against the cutout portions, such as ear 28 pressedagainst cutout 36, so that the secure connection between the shafts ofthe variable resistors and the connecting members may be greatlysimplified. Since it is not required to provide tapped holes in theshafts of the variable resistors, the machining of the shafts and theassembly can be greatly simplified, and the cost can be substantiallyreduced.

In the prior art devices, a stop member is attached to the root of thecontrol shaft where the latter contacts the spherical body in order tolimit the angular movement of the control shaft. That is, the angularmovement of the control shaft is limited because the stop membercontacts the side walls of the casing. However, the number of componentsis increased, and it is difficult to attain the required dimensionalaccuracies in assembly. Furthermore, the steps in the assembly areincreased.

However, according to the present invention, the angular movement of thecontrol shaft 7 is limited by the seat member 9 which is formed integralwith the bearing 4 which rotatably supports the spherical body fromwhich the control shaft extends. Therefore, unlike the prior artdevices, the provision of the stop member can be eliminated.Furthermore, since the control shaft is supported and limited in angularmovement by the seat member formed integral with bearing, the accuracyin angular movement of the control shaft can be attained so that theerror between the magnitudes of resistance of the opposed variableresistors can be minimized. Moreover, the number of assembly steps canbe reduced so that a labor saving can be attained.

According to the present invention, the insulating member is fitted overthe lower portion of the control shaft in order to provide electricalinsulation between the two connecting members 26, 27 and between thecontrol shaft 7 and the connecting members so that noise may beminimized in operation.

, In one variation of the present invention, instead of fitting theinsulating member over the lower portion 34 of the control shaft 7, theconnecting members 26 and 27 may be provided with insulating coatings 40as shown in FIGS. 8 and 9.

In another variation of the present invention, as shown in FIGS. 10-12,a reduced-diameter portion 41 is formed in the control shaft, and isfitted with a coiled spring 42 whose one end is fixed to the controlshaft 7 and whose the other end is brought into close contact with theconnecting members 26 and 27. Therefore, the control shaft 7 and theconnecting members 26, 27 which are made of metal may be alwayselectrically connected to each other so that the noise produced when thecontrol shaft makes contact with the connecting members or aredisconnected therefrom can be prevented.

We claim:

1. In a device for the simultaneous control of a plurality of variableresistors of the type having a casing, first and second pairs ofvariable resistors mounted on the casing with their rotary shaftsdirected into the casing, the resistors of each pair of resistors havingaxially aligned shafts, a separate slotted bow-shaped connecting memberextending between the shafts of each pair of resistors whereby thebow-shaped members together form a crossed bridge, and a control memberfor the device including a control shaft mounted in a spherical bearingand extending into the slots of the connecting members at theirintersection; the improvement wherein the end of each of said rotaryshafts extending into the casing is cut out, each end of each connectingmember having a hole therein shaped to fit over the end portion of arotary shaft and an ear extending from a side of the hole therein, saidconnecting members being mounted on said ends of the aligned rotaryshafts with the rotary shafts extending into the hole at the respectiveend of the respective connecting member and the ear of the connectingmember pressed against the cut out portion of the respective shaft.

2. The device of claim 1 wherein said holes are substantially D-shapedwith said ears extending from the straight edges of the respectiveholes.

3. The device of claim 2 wherein said ears extend from the edges of therespective holes in a direction toward the ends of the respective rotaryshafts.

I trol shaft.

6. The device of claim 1, comprising an insulating coating on eachconnecting member adjacent the sides of the respective slot, saidinsulating coating being positioned to provide electrical insulationbetween the connecting members and said control shaft.

1. In a device for the simultaneous control of a plurality of variableresistors of the type having a casing, first and second pairs ofvariable resistors mounted on the casing with their rotary shaftsdirected into the casing, the resistors of each pair of resistors havingaxially aligned shafts, a separate slotted bow-shaped connecting memberextending between the shafts of each pair of resistors whereby thebow-shaped members together form a crossed bridge, and a control memberfor the device including a control shaft mounted in a spherical bearingand extending into the slots of the connecting members at theirintersection; the improvement wherein the end of each of said rotaryshafts extending into the casing is cut out, each end of each connectingmember having a hole therein shaped to fit over the end portion of arotary shaft and an ear extending from a side of the hole therein, saidconnecting members being mounted on said ends of the aligned rotaryshafts with the rotary shafts extending into the hole at the respectiveend of the respective connecting member and the ear of the connectingmember pressed against the cut out portion of the respective shaft. 2.The device of claim 1 wherein said holes are substantially D-shaped withsaid ears extending from the straight edges of the respective holes. 3.The device of claim 2 wherein said ears extend from the edges of therespective holes in a direction toward the ends of the respective rotaryshafts.
 4. The device of claim 1 comprising an insulating member on saidcontrol shaft and positioned to electrically insUlate said control shaftfrom said connecting members.
 5. The device of claim 4 wherein saidinsulating member is an insulating sleeve positioned on said controlshaft.
 6. The device of claim 1, comprising an insulating coating oneach connecting member adjacent the sides of the respective slot, saidinsulating coating being positioned to provide electrical insulationbetween the connecting members and said control shaft.